Mackpro Posted July 28, 2023 Share Posted July 28, 2023 The start wire comes out the back of the fuse box and comes through the top 5 pin connector, 4th pin down. Then through the 16 pin connector on pin 9 Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535815 Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 Thank you Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535816 Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 So this ecm may not work, I depinned 29 on the x2 connector, which is testing as starter relay ecm ground, and the ecm is supplying 3.5v with the key on to this circuit. I don't think I'm supposed to have voltage there. Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535817 Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 I’ve seen 3.5 to 3.7 volts sent through some circuits to check continuity of circuit. I found this out with the EGR valve . If it doesn’t get the return voltage it will throw a open circuit code. But I’m not 100% sure in your case Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535818 Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 What’s last 6 of vin and I can run it through TechTool Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535819 Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 So 85 has 5v with key on, 12v in start. Truck is 012413 Ecm vin is 012416 Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535820 Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 Relay tests good 133 ohm, 86 has 20ohm resistance Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535822 Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Yes 85 should have 12 volts on it when key turned to start position. But you only have a few seconds to test it. , then you have to cycle the key and try again. Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535823 Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 Just now, Mackpro said: Yes 85 should have 12 volts on it when key turned to start position. But you only have a few seconds to test it. , then you have to cycle the key and try again. Should it have 5v key on, not start? Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535824 Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 Cuz it does lol Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535825 Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 Hmmm interesting. I don’t think it should. But I’m still looking Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535826 Share on other sites More sharing options...
mdixon Posted July 28, 2023 Author Share Posted July 28, 2023 What relay does the start position energize? I was testing power in the top fuse panel and the ems relay 1 in the lower left corner, when checking the switch side to ground it energizes a relay in the clutch area. I wasn't sure if that was normal but I'm thinking it's not. Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535827 Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 The tech tool only has me checking the start relay and wiring in the fuse panel by clutch pedal. It basically just had me do the same test that I sent you. There is only info on pin 85 when key is in start position. Doesn’t say what it should be with just key in on position. The troubleshooting shooting guide in tech tool for the Mid144 PPID-3 FMI-3 is exactly what I sent you. If 12 volts is at pin 85 when key is in start position then it says “ No fault found” and test ends. When you turn key on is the PTO lamp on in the dash? Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535828 Share on other sites More sharing options...
Solution mdixon Posted July 28, 2023 Author Solution Share Posted July 28, 2023 So there may have been some error on my part, after testing the relay I reinstalled it and checked the wiring on start and got 12v. Rehooked the wires up to the starter relay on the starter and it fired right up. Maybe when I checked the relay the other day I didn't install it correctly, but having a bad ecu I couldn't tell. All well, all better now 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535830 Share on other sites More sharing options...
Mackpro Posted July 28, 2023 Share Posted July 28, 2023 That’s good! Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-535833 Share on other sites More sharing options...
C A Transport Posted July 9 Share Posted July 9 On 7/28/2023 at 10:54 AM, mdixon said: So there may have been some error on my part, after testing the relay I reinstalled it and checked the wiring on start and got 12v. Rehooked the wires up to the starter relay on the starter and it fired right up. Maybe when I checked the relay the other day I didn't install it correctly, but having a bad ecu I couldn't tell. All well, all better now Hey I'm having same exact problem what would you say the issue really was ? Quote Link to comment https://www.bigmacktrucks.com/topic/73097-no-start-no-crank/page/2/#findComment-554940 Share on other sites More sharing options...
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